Got nothing to do with CDI's, RMI's or any type of pointer guys. It's dimensional.
2D = 2 Dimensions
3D = 3 Dimensions
2D Approaches only gives you guidance with direction
3D Approaches gives you guidance in direction and altitude (G/S)
Note, altitude steps on a 2D approach is not altitude guidance.
Yes, NDB app renews VOR and RNAV and vice versa. They all renew each other regardless of the pointer/CDI used. They are all 2D approaches.